using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Reflection;

namespace Hncore.Infrastructure.Extension
{
    /// <summary>
    /// EF上下文对象扩展类
    /// </summary>
    ///
    public static class DbContextExtension
    {
        /// <summary>
        /// 执行SQL返回受影响的行数
        /// </summary>
        public static int ExecSqlNoQuery(this DbContext db, string sql, DbParameter[] sqlParams = null)
        {
            return ExecuteNoQuery(db, sql, sqlParams);
        }
        /// <summary>
        /// 执行存储过程返回IEnumerable数据集
        /// </summary>
        public static IEnumerable<T> ExecProcQuery<T>(this DbContext db, string sql, DbParameter[] sqlParams = null) where T : new()
        {
            return Execute<T>(db, sql, CommandType.StoredProcedure, sqlParams);
        }
        /// <summary>
        /// 执行存储过程返回IEnumerable数据集
        /// </summary>
        public static DataSet ExecProcDataSet(this DbContext db, string sql, DbParameter[] sqlParams = null)
        {
            return ExecuteDataSet(db, sql, CommandType.StoredProcedure, sqlParams);
        }
        /// <summary>
        /// 执行sql返回IEnumerable数据集
        /// </summary>
        public static IEnumerable<T> ExecSqlQuery<T>(this DbContext db, string sql, DbParameter[] sqlParams = null) where T : new()
        {
            return Execute<T>(db, sql, CommandType.Text, sqlParams);
        }
        /// <summary>
        /// 执行SQL并返回受影响的行数
        /// </summary>
        /// <param name="db"></param>
        /// <param name="sql"></param>
        /// <param name="sqlParams"></param>
        /// <returns></returns>
        private static int ExecuteNoQuery(this DbContext db, string sql, DbParameter[] sqlParams)
        {
            DbConnection connection = db.Database.GetDbConnection();
            DbCommand cmd = connection.CreateCommand();
            int result = 0;
            db.Database.OpenConnection();
            cmd.CommandText = sql;
            cmd.CommandType = CommandType.Text;
            if (sqlParams != null)
            {
                cmd.Parameters.AddRange(sqlParams);
            }
            result = cmd.ExecuteNonQuery();
            db.Database.CloseConnection();
            return result;
        }
        /// <summary>
        /// 执行SQL，返回查询结果
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="db"></param>
        /// <param name="sql"></param>
        /// <param name="type"></param>
        /// <param name="sqlParams"></param>
        /// <returns></returns>
        private static IEnumerable<T> Execute<T>(this DbContext db, string sql, CommandType type, DbParameter[] sqlParams) where T : new()
        {
            DbConnection connection = db.Database.GetDbConnection();
            DbCommand cmd = connection.CreateCommand();
            DataTable dt = new DataTable();
            try
            {
                db.Database.OpenConnection();
                cmd.CommandText = sql;
                cmd.CommandType = type;
                if (sqlParams != null)
                {
                    cmd.Parameters.AddRange(sqlParams);
                }              
                using (DbDataReader reader = cmd.ExecuteReader())
                {
                    dt.Load(reader);
                }
            }
            finally
            {
                db.Database.CloseConnection();
            }
            return dt.ToCollection<T>();
        }
        /// <summary>
        /// 执行SQL，返回查询结果
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="db"></param>
        /// <param name="sql"></param>
        /// <param name="type"></param>
        /// <param name="sqlParams"></param>
        /// <returns></returns>
        private static DataSet ExecuteDataSet(this DbContext db, string sql, CommandType type, DbParameter[] sqlParams)
        {
            DbConnection connection = db.Database.GetDbConnection();
            DbCommand cmd = connection.CreateCommand();
            db.Database.OpenConnection();
            cmd.CommandText = sql;
            cmd.CommandType = type;
            if (sqlParams != null)
            {
                cmd.Parameters.AddRange(sqlParams);
            }
            DataSet ds = new DataSet();
            using (DbDataReader reader = cmd.ExecuteReader())
            {
                ds.Load(reader,LoadOption.PreserveChanges,"data","info");
            }
            db.Database.CloseConnection();
            return ds;
        }
    }

    /// <summary>
    /// DataTable扩展类
    /// </summary>
    ///
    public static class ExtendDataTable
    {
        /// <summary>
        /// 将对象转换成DataTable
        /// </summary>
        /// <typeparam name="T">源对象类型</typeparam>
        /// <param name="data">源对象列表</param>
        /// <returns>转换后的DataTable</returns>
        ///
        public static DataTable ToDataTable<T>(this IEnumerable<T> data)
        {
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
            var table = new DataTable();
            foreach (PropertyDescriptor prop in properties)
                table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
            foreach (T item in data)
            {
                DataRow row = table.NewRow();
                foreach (PropertyDescriptor prop in properties)
                    row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
                table.Rows.Add(row);
            }
            return table;
        }

        /// <summary>
        /// 将DataTable首行转换成目标对象
        /// </summary>
        /// <typeparam name="T">目标对象类型</typeparam>
        /// <param name="dt">源DataTable对象</param>
        /// <returns>转换后的目标对象</returns>
        ///
        public static T ToEntity<T>(this DataTable dt) where T : new()
        {
            IEnumerable<T> entities = dt.ToCollection<T>();
            return entities.FirstOrDefault();
        }

        /// <summary>
        /// 将DataTable转换成目标对象列表
        /// </summary>
        /// <typeparam name="T">目标对象类型</typeparam>
        /// <param name="dt">源DataTable对象</param>
        /// <returns>转换后的目标对象列表</returns>
        ///
        public static IEnumerable<T> ToCollection<T>(this DataTable dt) where T : new()
        {
            if (dt == null || dt.Rows.Count == 0)
            {
                return Enumerable.Empty<T>();
            }
            IList<T> ts = new List<T>();
            // 获得此模型的类型 
            Type type = typeof(T);
            string tempName = string.Empty;
            foreach (DataRow dr in dt.Rows)
            {
                T t = new T();
                PropertyInfo[] propertys = t.GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    tempName = pi.Name;
                    //检查DataTable是否包含此列（列名==对象的属性名）     
                    if (dt.Columns.Contains(tempName))
                    {
                        // 判断此属性是否有Setter   
                        if (!pi.CanWrite) continue;//该属性不可写，直接跳出   
                        object value = dr[tempName];
                        if (value != DBNull.Value)
                        {
                            if (!pi.PropertyType.IsGenericType)
                            {
                                value = Convert.ChangeType(value, pi.PropertyType);
                                pi.SetValue(t, value);
                            }
                            else {
                                Type genericTypeDefinition = pi.PropertyType.GetGenericTypeDefinition();
                                if (genericTypeDefinition == typeof(Nullable<>))
                                {
                                    value = Convert.ChangeType(value, Nullable.GetUnderlyingType(pi.PropertyType));
                                    pi.SetValue(t, value);
                                }
                            }
                        }       
                    }
                }
                ts.Add(t);
            }
            return ts;
        }
    }
}